Playing as much of the move as possible
As you know, you must play your move if possible. You are not entitled to refuse it. It sometimes happens that you get, say, a 6-2 in a Situation where none of your men, as they presently are, can move 6. In that case you must, if you can, play a 2 in such a way that the man moved can then move the 6 afterwards.
In Diagram, for instance, you (White) would much rather not be able to play your 6. However, you can play 2-6 and you are obliged to move a man on Black's twelve point to your eleven point and on to your five point, thus leaving Black a double shot at your remaining man on bis twelve point.
Sometimes you can play part of your move but not all of it. In Diagram, you throw 5-3. You have a possible 5 and a possible 3, but not both. You would rather play the 3, making Black's eight point, but the rules require you to play the higher number, the 5, so you have to leave two blots.